Renewable cutting edge for plowshares



April 9, 1963 H. E. LINDEN 3,084,750

RENEWABLE CUTTING EDGE FOR PLOWSHARES Original Filed Aug. 2, 1955 2Sheets-Sheet 1 INVENTOR. Aueeeer 1 Z/NOEA/ I ulf/orngy:

April 9, 1963 H. E. LINDEN 3,034,750

RENEWABLE CUTTING EDGE FOR PLOWSHARES Original Filed Aug. 2, 1955 2Sheets-$11991- 2 INVENTOR. A zzseer E. [wpsu United States PatentClaims. Cl. 172-719 This is a continuation of application Serial No.526,052 filed by me August 2, '1955, now abandoned, which in turn is acontinuation-in-part of application Serial No. 247,822 filed by meSeptember 22, 1951, and now abancloned.

The present invention relates generally to renewable cutting edges foragricultural and earth-working implements and more particularly to animproved renewable cutting edge for plowshares.

Conventional plows usually include a chassis arranged to be propelled bysuitable means, a moldboard secured to the chassis, and a plowshare ofconsiderable width ordinarily attached to the moldboard by suitablefastening means, such as nuts and bolts. The plowshares are quiteexpensive because of the necessity of forming them of a metal havinglong-wearing qualities and because of their size and peculiar shape,which shape must be such that the cutting edge of the plowshare willhave a low friction in passing through earth. Ordinarily it is only thepoint and cutting edge of the plowshare which is worn away in use, andwhen this occurs, the user is required to remove the entire plowsharefrom the moldboard and take it, at considerable expense and vexatiousdelay, to be resharpened. In order to avoid such expense and delay therehave been heretofore proposed several types of renewable cutting edgeswhich may be applied to the face of the plowshare so as to fit over theoriginal cutting edge.

The majority, but not all, of these heretofore-proposed renewablecutting edges have been adapted for use with plowshares of standardconstruction and have proved to be reasonably satisfactory in use. Ithas been found, however, that these renewable cutting edges have beenquite expensive whereby the margin of difference between resharpeningthe original cutting edge of the plowshare and purchasing a renewablecutting edge is not very outstanding. This small expense margin whencombined with the added weight of the heretofore-proposed renewablecutting edges has proved to be a considerable deterrent to wideacceptance of these devices. The chief cause of the comparatively highcost of these devices arises from the difficulty of rigidly securingthem to the face of the plowshares, which difficulty is due to the factthat the face of the conventional plowshare is formed with a concavelongitudinal curvature. In order to make the renewable cutting edgeconform to this concave curvature, it is customary to form them with aplurality of upstanding fingers rigidly secured at their lower endsalong the length of the blade of the renewable cutting edge. Therenewable cutting edge is secured to the plowshare by forcing theseattachment fingers away from the rear of the blade of the cutting edgeand slipping this blade over the lower edge of the plowshare. Thereafterthese fingers will exert a frictional pressure between the plowshare andthe rear blade. These attachment fingers not only contribute appreciablyto the cost of the conventional renewable cutting edge, but they alsocontribute to a considerable extent to the weight thereof. Additionally,these fingers do not always provide a sufficiently rigid engagement ofthe renewable cutting edge with the ice face of the plowshare,especially where the plow is utilized to work heavy soils.

It is a major object of my present invention to provide a renewablecutting edge for plowshares which is very economical of construction andlight in weight as compared to existing cutting edges of this type.These improvements are due primarily to my provision of novel means forattaching the renewable cutting edge to a plowshare, which meanseliminate the need of attachment fingers or any like devices along thelength of the blade of the renewable cutting edge.

It is another object of this invention to provide a renewable cuttingedge for plowshares having novel means for attaching the blade thereofto a plowshare, which means is capable of effecting rigid engagement ofthe blade of the renewable cutting edge with the face of the plowshareunder even the most adverse working conditions.

A further object of the present invention is to provide a renewablecutting edge for plowshares which is readily installed upon and removedfrom a plowshare without requiring the use of any special tools.

It is yet another object of the present invention to provide a renewablecutting edge for plowshares which will fit a standard plowshare withoutnecessitating any alteration thereof.

Another advantage of the preferred form of renewable plowshare edgeembodying my present invention is its improved resistance to wear overheretofore-proposed renewable edges. Such wear resistance is obtained bymeans of a unique dipping process.

It is an important object of this invention to provide a renewablecutting edge for plowshares having means for restraining the entrance ofsoil between the rear of the blade of the cutting edge and the face ofthe plowshare. This feature is of considerable advantage inasmuch as itoften occurs when conventional renewable cutting edges are utilized towork certain fine soils, especially of the sandy type, soil willgradually work its way between the back surface of the blade of thecutting edge and the face of the plowshare so as to force the blade awayfrom the face. When this happens the renewable cutting edge no longerhas the same configuration as the face of the plowshare and the frictionof the cutting edge as it passes through earth will be increased. It mayalso occur that this building up of soil between the plowshare and therenewable cutting edge will result in disengagement of the renewablecutting edge from the plowshare.

Another object of the present invention is to provide a renewablecutting edge for plowshares having means for maintaining its bladetightly against the face of the plowshare whereby it will retainsubstantially the same longitudinal configuration thereof.

An additional object of this invention is to provide a renewable cuttingedge for plowshares which may be entirely formed from a single metallicblank.

It is yet another object of the present invention to provide a renewablecutting edge for plowshares which, although capable of providing all ofthe aforementioned features, is of extremely simple and sturdyconstruction.

Other objects and advantages will become apparent from the followingdetailed description, taken in conjunction with the accompanyingdrawings, wherein:

FIGURE 1 is a side elevational view of a conventional plowshare to whichis attached a preferred form of renewable cutting edge embodying thepresent invention;

FIGURE 2 is a generally horizontal view taken on line 22 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary view of a detail of construction ofa renewable cutting edge embodying the present invention;

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 3;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 3;

FIGURES 6 and 7 are enlarged vertical sectional views taken on line 66of FIGURE 1 and showing alternate shapes which may be assumed by theblade of a renewable cutting edge formed in accordance with the presentinvention;

FIGURE 8 is a perspective view of the renewable cutting edge shown inFIGURES 1 and 2;

FIGURE 9 is an enlarged sectional view taken on line 99 of FIGURE 8; and

FIGURE 10 is a broken plan view of a metallic blank from which may beformed an alternate form of cutting edge embodying the presentinvention.

FIGURE :11 is a greatly enlarged fragmentary vertical sectional viewsimilar to FIGURE 6 showing a modified form of cutting edge embodyingthe present invention.

Referring to the accompanying drawings, and particularly to FIGURE 1thereof, there is shown the moldboard of a conventional plow with aplowshare, generally designated 22, secured thereto. The plowshare 22 isformed with a landside or face 24, a point 26, a heel 28 and a cuttingedge 30. When this original cutting edge 30 becomes dull or damaged, arenewable cutting edge, generally designated 32, formed in accordancewith the present invention may be affixed to the lower portion of theplowshare, as indicated in FIGURES 1 and 2. Preferably, this renewablecutting edge 32 broadly comprises an elongated blade 34, a front pocket,generally designated 36, adapted to be fitted over the point 26, and arear clamp, generally designated 38, adapted to be fitted over the heel28. The profie of the blade 34 is seen to closely follow the profile ofthe plowshare 22, being curved downwardly at its front portion tocorrespond to the peculiar shape of the plowshare at this point with thebottom 49 of the new cutting edge approximating closely the line of theoriginal cutting edge 30.

With particular reference to FIGURE 2, it will be observed that the face24 of the plowshare 22 is formed with a concave longitudinal curvature41. It is an important feature of the present invention that the blade34 of the renewable cutting edge 32 may be caused to assume and retainthis curvature without the use of the heavy and expensive attachmentfingers found on the ordinary cutting edge. In order to eliminate suchattachment fingers, the blade 34 is not straight, as is the case withconventional renewable cutting edges, but instead it is formed with anormal concave longitudinal curvature greater than the curvature of theplowshare as indicated by the dotted lines in FIGURE, i.e. having aradius of curvature less than that of the plowshare face. By virtue ofthis longitudinal curvature, once the front and rear ends of therenewable cutting edge 32 are secured to the point and heel of theplowshare, the blade 34 will be fixed or sprung tightly against the face24. As shown in FIGURE 2, the normal longitudinal curvature of the bladein its relaxed condition will be such that when the front pocket 36 isengaged with the point 26 the major portion of the blade 34 tends tocurve away from the face 24 with the rear of the blade being disposedmost remotely therefrom. It is important, however, that the curvaturestarts near the front of the blade in order to obtain best results,since if it starts farther to the rear the blade will not always fittightly against the face.

Referring again to FIGURES 1 and 2, in order to install the renewablecutting edge 32 upon the plowshare 22, the front pocket 35 is firstslipped over the point 26 thereof. At this time the renewable cuttingedge is disposed approximately as indicated by the lightly dottedoutline in these figures with the upper edge of the rear portion thereofbeing spaced somewhat below the heel 28. Next, the rear of the renewablecutting edge is moved upwardly, and also inwardly toward the heel 28 ina direction which is indicated by the arrow in FIGURE 1, until the rearclamp 38 encompasses the heel. As soon as this movement has beenaccomplished, the renewable cutting edge 32 will be held firmly inplace.

The front pocket 36 may be readily formed from the same piece ofmaterial as the blade by bending the forward portion of the blade backupon itself so as to form a side wall 41b, as shown in FIGURE 3. Theforward edge 42 of this pocket will preferably be shaped in conformitywith the lower portion of the plowshare point 26. When the front pocketis fitted over this point, the latter is adapted to snugly seattherewithin until such time as it becomes desira 'le to remove therenewable cutting edge 32 from the plowshare. At this time the rear ofthe renewable cutting edge 32 must be lowered in a reversal of theinstallation procedure described previously above. It should be observedthat it is possible to form the front pocket 36 by a separate castingoperation rather than from the material of the blade.

The rear clamp 38 will preferably be formed from the same piece ofmaterial as the blade 34. As shown in FIGURES 8 and 9, it may consist ofan upstanding side wall 44 and a bottom wall 46 which are both struckout of the rear portion of the blade 34.

\eferring again to FIGURE 3, it is commonly known that a metal which hashigh wear resistance is generally quite difficult to form into variousshapes. Thus, if the blade is made from a metal which is sufiicientiyductile to permit it to be formed into a front pocket and a rear clamp,it may not possess s'ufficient wear resistance for use under alloperating conditions. Of course this defect may be cured by theapplication of a hard facing material, such as tungsten carbide or thelike, to the lower cutting portion thereof, however, the cost of thisprocedure may be quite high. Hence, I have found it desirable to formthe blade of a metal having a high wear resistance and forming the frontpocket separately therefrom. The front pocket may then be rigidlyaifixed, as by welding, to the front end of this blade. As notedhereinabove the front pocket may be of cast construction utilizing ametal which also has a high wear resistance, such as manganese steel. Asshown in FIGURE 3, this front pocket 36b may be welded to the front edgeof the blade 34b as by a tension weld 62.

It is an important feature of the present invention that should it bedecided to form the entire renewable cutting edge from a single piece ofmaterial the operation may be performed in a single operation. Thus,referring to FIGURE 10, a blank, generally designated 64, may be stampedor otherwise cut out which includes an elongated blade portion 34, afront portion 6a which may be folded over so as to form a front pocket,and a rear portion 68 which may be struck out so as to form a rearclamp. This blank may be inserted within a suitable forming press so asto simultaneously form the front pocket and rear clamp. The normalconcave longitudinal curvature shown in FIGURES 2 and 8 maybe readilyformed when stamping out the blank 64.

It will be readily apparent that a steel having sufficient flexibilityto resiliently retain the necessary longitudinal curvature of the blade34' may not possess adequate resistance to wear. In order to overcomethis disadvantage, I aluminize the renewable cutting edge 32 in aspecial manner. Thus, the renewable cutting edge 32 is first cleaned andpickled and then immersed in a molten layer of salt existing atapproximately l550 F. A layer of molten aluminum is disposed above themolten salt layer. After the renewable cutting edge 32 has been heatedto a desired temperature by the molten salt it is raised through themolten aluminum layer. As the cutting edge 32 passes through and out ofthe molten aluminum it receives a coating thereof. After being removedfrom the molten aluminum the cutting edge 32 is quenched in ans arseoil. Thereafter, it is drawn for about 3 to 4 minutes at approximately800 P. so as to be stress relieved.

The above described process acts as a combination heat treating andaluminum coating process for the renewable cutting edge 32. The aluminumcoating process eliminates a separate painting operation and providesthe renewable cutting edge 32 with excellent corrosion resistancequalities. The intermetallic aluminum-steel compound is very hard(approximately 4SS() Rockwell C) so as to provide the blade of therenewable cutting edge with adequate wear resistance even under adverseworking conditions. Such wear resistance will approximate that of theplowshare. At the same time the blade retains sufficient resiliency forretaining the necessary ngitudinal curvature required to insure itsself-retention on the plowshare. A greatly enlarged vertical section ofthe aluminized cutting edge 32 is shown in FIGURE 11, the aluminumcoating being indicated by the numeral 80, and the aluminum-metallicinterlayer being indicated by the numeral 81.

Another important advantage afforded by the present invention is that ofnovel means for restraining the entrance of soil between the backsurface of the blade of a renewable cutting edge and the face of theplowshare whereon it is mounted. Thus, referring to FlGURE 6, there isshown a vertical sectional view of the blade 34 of one form of therenewable cutting edge 32 of FIGURE 1. It will be seen that the backsurface 7b of this blade 34 rests against the face 24 of the plowshare22. It will be apparent that unless the blade 34 is urged very tightlyagainst the face 24, it will be possible for certain fine soils,especially of the sandy type, to be forced through the space 72. upwardsbetween the blade and the face. As mentioned previously, hereinbefore,any build-up of soil between the blade and the face of the plowshare isdetrimental to the effective operation of the plow and may also resultin eventual disengagement of the renewable cutting edge from theplow-share. Accordingly, in an effort to prevent such occurrence, it hasbeen found desirable to transversely offset the lower portion of theblade 34c as shown in FIGURE 7 at 74, whereby this lower portion coversthe original cutting edge of the plowshare 22. By this arrangement theentrance of soil between the blade 34c and the face 24 of the plowshareis effectively restrained. In order to provide a more effective seal theoriginal cutting edge of the plowshare may be rounded off as indicatedat 76 of this figure.

As stated above, a renewable cutting edge formed in accordance with theforegoing description will closely conform to the configuration of theoriginal plowshare. For this reason the original line of draft of theplowshare will not be adversely affected. Hence, there will not berequired the application of an appreciable amount of additional power inorder to compensate for the use of my renewable cutting edge, as hasbeen true of certain heretofore-proposed renewable cutting edges. Also,it should be observed that a cutting edge built in accordance with thepresent invention does not incorporate any pro tuberances along thelength lOf its blade liable to interrupt the free flow of soiltherealong as the plowshare is moved through the earth. Hence, thefriction developed by a plowshare mounting a renewable cutting edge ofthis type will not be substantially greater than the friction developedby the bare plowshare alone.

Despite the lack of friction-causing protuberances along 6 the length ofmy blade it will remain firmly affixed to the plowshare, the engagementof the front pocket 36 with the 6 plowshares point 26 resisting alltendency of the earth to dislodge the renewable cutting edge rearwardlyduring a plowing operation.

It will be apparent to those skilled in the art that variousmodifications and changes may be made without departing from the spiritof the invention or the scope of the appended claims.

I claim:

1. A renewable cutting edge for a plowshare comprising a flexible,resilient, elongated blade having a substantial width in relation to itsthickness and a sharpened edge, a front pocket formed at the forward endof said blade for receiving the point of the plowshare, and a rear clampformed at the rear portion of said blade for receiving the heel of theplowshare, said front pocket and rear clamp cooperating with the pointand heel of the plowshare to secure the forward and rear ends of theblade against transverse movement relative to the plowshare with theinner face of said blade against the outer face of the plowshare andsaid sharpened edge extending beyond the original cutting edge of theplowshare, said front pocket also cooperating with said point torestrain said blade against rearward longitudinal movement rela tive tothe plowshare during forward movement of the latter through the soil,said blade having a long substantially smooth and continuousintermediate portion between said front pocket and said rear clamp toprovide an overall cutting profile olosely approximating the originalcutting edge of the plowshare with which it is used, said intermediateportion of said blade having a normal curvature in a direction normal tothe plane of said blade to provide a normally convex rear face, saidcurvature commencing near said forward end and being substantiallygreater than the curvature of the outer face of the plowshare to urgethe rear face of said intermediate portion by spring action into snugcontinuous engagement throughout its length with the outer face of theplowshare when said front pocket and rear clamp are engaged with theplowshare so as to restrain the entrance of soil between the rear faceof said blade and the front face of the plowshare, said blade being free:of positive connection to the plowshare between said front pocket andrear clamp so that said intermediate portion is restrained againstmovement away from the plowshare solely by said spring action.

2. A renewable cutting edge as recited in claim 1 wherein the lowerportion of said blade is offset rearwardly to cover the original cuttingedge of the plowshare and extends downwardly from said offsetsubstantially in the plane of the plowshare.

3. A renewable cutting edge as recited in claim 1 wherein said frontpocket is welded to the forward end of said intermediate portion'of saidblade.

4. A renewable cutting edge as recited in claim 1 wherein said frontpocket and said rear clamp are integral with said blade.

5. A renewable cutting edge as recited in claim 4 wherein said rearclamp is struck out from said blade.

References Cited in the file of this patent 9 UNITED STATES PATENTS187,659 McIntyre Feb. 20, 1877 1,925,779 Tomlinson Sept. 5, 19332,073,801 Linden Mar. 16, 1937 2,508,542 Sacksteder May 23, 1950

1. A RENEWABLE CUTTING EDGE FOR A PLOWSHARE COMPRISING A FLEXIBLE,RESILIENT, ELONGATED BLADE HAVING A SUBSTANTIAL WIDTH IN RELATION TO ITSTHICKNESS AND A SHARPENED EDGE, A FRONT POCKET FORMED AT THE FORWARD ENDOF SAID BLADE FOR RECEIVING THE POINT OF THE PLOWSHARE, AND A REAR CLAMPFORMED AT THE REAR PORTION OF SAID BLADE FOR RECEIVING THE HEEL OF THEPLOWSHARE, SAID FRONT POCKET AND REAR CLAMP COOPERATING WITH THE POINTAND HEEL OF THE PLOWSHARE TO SECURE THE FORWARD AND REAR ENDS OF THEBLADE AGAINST TRANSVERSE MOVEMENT RELATIVE TO THE PLOWSHARE WITH THEINNER FACE OF SAID BLADE AGAINST THE OUTER FACE OF THE PLOWSHARE ANDSAID SHARPENED EDGE EXTENDING BEYOND THE ORIGINAL CUTTING EDGE OF THEPLOWSHARE, SAID FRONT POCKET ALSO COOPERATING WITH SAID POINT TORESTRAIN SAID BLADE AGAINST REARWARD LONGITUDINAL MOVEMENT RELATIVE TOTHE PLOWSHARE DURING FORWARD MOVEMENT OF THE LATTER THROUGH THE SOIL,SAID BLADE HAVING A LONG SUBSTANTIALLY SMOOTH AND CONTINUOUSINTERMEDIATE PORTION BETWEEN SAID FRONT POCKET AND SAID REAR CLAMP TOPROVIDE AN OVERALL CUTTING PROFILE CLOSELY APPROXIMATING THE ORIGINALCUTTING EDGE OF THE PLOWSHARE WITH WHICH IT IS USED, SAID INTERMEDIATEPORTION OF SAID BLADE HAVING A NORMAL CURVATURE IN A DIRECTION NORMAL TOTHE PLANE OF SAID BLADE TO PROVIDE A NORMALLY CONVEX REAR FACE, SAIDCURVATURE COMMENCING NEAR SAID FORWARD END AND BEING SUBSTANTIALLYGREATER THAN THE CURVATURE OF THE OUTER FACE OF THE PLOWSHARE TO URGETHE REAR FACE OF SAID INTERMEDIATE PORTION BY SPRING ACTION INTO SNUGCONTINUOUS ENGAGMENT THROUGHOUT ITS LENGTH WITH THE OUTER FACE OF THEPLOWSHARE WHEN SAID FRONT POCKET AND REAR CLAMP ARE ENGAGED WITH THEPLOWSHARE SO AS TO RESTRAIN THE ENTRANCE OF SOIL BETWEEN THE REAR FACEOF SAID BLADE AND THE FRONT FACE OF THE PLOWSHARE, SAID BLADE BEING FREEOF POSITIVE CONNECTION TO THE PLOWSHARE BETWEEN SAID FRONT POCKET ANDREAR CLAMP SO THAT SAID INTERMEDIATE PORTION IS RESTRAINED AGAINSTMOVEMENT AWAY FROM THE PLOWSHARE SOLELY BY SAID SPRING ACTION.